The volume of data associated with wireless user equipment and wireless networks is continually increasing. Reasons include the increasing variety of user equipment (e.g., ultra-mobile laptops, personal digital assistants (PDAs)), and the broadening variety of web services, particularly high bandwidth services. As an illustration, vehicle on-board computer systems, having access to various subscription-based information and entertainment services, such as movies, are becoming commonplace.
One goal of wireless systems, from the perspective of both users and providers, is global mobility, meaning reliable, secure connections across all geographical areas to uninterrupted services such as e-mail, web browsing, virtual office networking, publish-subscribe systems, telephony communications, and various web business services. Related goals are fair and efficient allocation of bandwidth and accurate monitoring of use to enable accurate and flexible billing for services provided.
The Universal Mobile Telecommunication System (UMTS), developed under the Third Generation Partnership Project (3G) cellular network standard, was developed in view of these and other goals.
An improvement of the UMTS 3G system, termed the Long Term Evolution (LTE) next generation system, is foreseen as a next significant step towards these and other goals, namely global mobile service for the user and accurate monitoring, billing, control, and maintenance of communication traffic. LTE is also seen as helping to meet anticipated bandwidth requirements of likely increases in use of services such as, for example, Multimedia Online Gaming (MMOG), mobile TV, mobile podcasting, and other various streaming media.
LTE is an all-packet system, currently referred to in the industry as the Evolved Packet System (EPS). Its specification is sufficiently established such that various significant efforts toward large-scale commercial deployment are underway.
LTE was developed in view of an ongoing market shift toward all-IP mobile access systems, to provide capacity, reliability, scalability, and added revenue generation models and options, including quality of service (QoS) based packet prioritization and billing.
The LTE specification is well known, and readily accessible to the public. For purposes of convenience and background, the 3GPP LTE Specification, Release 8, available from 3GPP, is hereby incorporated by reference.
LTE will likely provide significant improvements over UMTS in terms of bandwidth, mobility, revenue, scalability, flexibility, inter-operability, and other parameters. However, LTE was developed to meet a very broad range of requirements. For example, one LTE objective is a flat IP network architecture, and its specifications and functions are further to this objective. The present inventors have identified potential limitations and shortcomings.
One such limitation relates to assignment of default bearers. When a communication is initiated in an LTE system, an attachment process assigns bearers to the communication. First, a default bearer without a Guaranteed Bandwidth Rate (GBR) is established for signaling traffic with the user's base station (e.g., between the eNodeB and the serving or “S-GW” facing the eNodeB) and any non-GBR traffic, like “best-effort” data. In addition, a dedicated bearer with a GBR specific to the application (e.g., voice call) may be set-up if required by the user. Since only dedicated bearers have guaranteed QoS, they have priority over the default bearers. Therefore, when congestion occurs, traffic carried in default bearers for UE on S-GW will likely be buffered or discarded, depending on the amount of traffic allowed and offered on the dedicated bearers. As a result, various applications that may use default bearer, including signaling, may be negatively impacted, to an extent including failure.
It has been proposed, for overcoming the potential of dedicated bearer traffic impacting default bearer traffic, to provide a different dedicated bearer for each application or group of applications (e.g., voice, video, MMS). However, such an arrangement requires numerous bearers and related resources at the S-GW and MME and, further, may result in substantial overhead.
In addition, charging/credit policy may be required against a default bearer in the S-GW. Mixing different applications and signaling traffic, however, may result in errors in the above and would not allow per-application level charging/credit/policy.
There are existing mechanisms such as, for example, differential services control point (DSCP) marking for differential services (DiffServ), directed to providing QoS priority and application differentiation in IP networks. However, DiffServ is only a packet-loss prioritization, in which IP packets are marked with one of three (3) drop precedence values, the lower the value the higher the priority of not dropping the packet. Such mechanisms can be acceptable for well-controlled application/services, but fall short for over-the-top (OTT) applications classified as part of the default bearer traffic, such as OTT Voice Over IP (VoIP) data like Skype or partner content delivered over the Internet.